534
FXUS66 KOTX 132101
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
201 PM PDT Sun Sep 13 2026

.KEY MESSAGES...

- Showers and isolated thunderstorms Sunday evening slowly
  ending from west to east by Monday morning.

- Risk for debris flows and rock slides in Central Washington
  near sensitive burn scars and steep terrain.

- Mountain showers Tuesday with breezy north to northeast winds.

- Warming and drying trend Wednesday into the weekend with
  temperatures rebounding into the 70s-80s by the end of the
  week.

&&

.SYNOPSIS...
Steady rain over Central Washington will slowly diminish.
Scattered showers with isolated thunderstorms will continue
through the night across the Idaho Panhandle and Eastern
Washington. Fair weather conditions on Monday then another
disturbance will bring breezy winds and mountain showers on
Tuesday. Warmer and drier mid to late week.

&&

.DISCUSSION...
Tonight: The robust area low pressure system responsible for
the last 12+ hours of rainfall will begin its trek eastward out
of the region. Rain will diminish from west to east clearing
out of Central WA this evening and linger across the Idaho
Panhandle until early Monday morning. Rainfall amounts in the
last 24 hours have been quite impressive for southern Chelan
County (1-2 inches) and 0.50-1.00 inches for many communities
across northern and northeastern WA including the Spokane Area.
As clouds clear out, I anticipate areas of fog to settle into
areas where winds remain light. Locally breezy conditions will
continue across southeastern which will favor low clouds vs fog
including Pullman and Spokane area.

Monday-Tuesday: Monday will bring a break in the precipitation
with light winds but continued cooler than normal temperatures
with the region under the influence of a broad upper-level
trough. A reinforcing shortwave will drop into the trough from
the north on Tuesday. This wave has trended stronger and
stronger over the last few days bringing a 30-60% chance for
showers across the northern mountains and down the spine of the
Cascades. Rainfall amounts will be lighter and largely between a
few hundredths to a tenth with locally around a quarter of an
inch on the peaks near the International Border. Shifting winds
are expected as the wave progresses through the region starting
off from the southwest Monday then shifting to the east Tuesday
morning and north to northeast Tuesday afternoon and night.
Locally breezy conditions will be possible through the Okanogan
Valley and Waterville Plateau as winds shift to the north.

Wednesday-Sunday: The upper-low will dig into N CA/southern OR
and continue to spin there for a few days before ejecting to
the east. Meanwhile, an upper-level ridge will expand into the
region from the Ern Pac with heights rising along the
International border. This typically leads to low confidence
where these cutoff lows will drift and uncertainty how quickly
it will depart the west. This pattern also suggest a trend
toward drier conditions for much of the Inland NW. The exception
will be far SE WA and the lower ID Panhandle with potential for
moisture over the Great Plains to get pulled westward across
Eastern Oregon and skirt the far southeastern portion of the
forecast area. Otherwise, temperatures will rebound into the 70s
Wednesday then 70-80s Thursday into the weekend. Over 50% of
the ensembles hint at a Pacific trough influencing the region by
early next week. /sb

&&

.AVIATION...
18Z TAFS: Steady rain wrapping around a robust low pressure will
remain steady across the northern mountains and into Central WA
through 00z. A midlevel dry slot nosing across southeastern WA
and into the Spokane-Cd`A is allowing for sunbreaks but
increasing instability and threat for hit or miss convective
showers. There is also a risk for isolated thunderstorms with
the greatest risk around KLWS-KPUW (20% chance). Winds will be
gusty through much of the afternoon with gusts 20-30 mph and
direction largely counter clockwise around the low that
currently resides near Ephrata, WA. Heading into the evening,
the system will begin to track east with rain ending in Central
WA and showers increasing along the ID/WA border. This will also
bring a 50% chance or higher of cigs lowering MVFR to local IFR.
KEAT looks to maintain a light NW wind overnight leading to low
probabilities for fog but sheltered areas will carry some risk,
including KMWH.


FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Main uncertainty
through the day will be wavering visibility and cigs with
fluctuations in rain intensities. Next will be thunderstorm
coverage around KLWS-KPUW and if cells can develop KGEG-KCOE.
Last will be how low cigs become and coverage of fog following
the departure of a very moist storm system. Confidence moderate
for KGEG given a favorable boundary layer wind.

-----------------------

Confidence descriptors:
Low - Less than a 30 percent chance
Moderate - 30 to 70 percent chance
High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane
airports, please refer to the Aviation Dashboard on our
webpage: https:/www.weather.gov/otx/avndashboard

&&

.Preliminary Point Temps/PoPs...
Spokane        45  67  45  66  45  73 /  70   0   0  10  10   0
Coeur d`Alene  45  63  44  64  45  72 /  90  20   0  10  10   0
Pullman        47  64  41  66  41  72 /  90   0   0   0  10   0
Lewiston       48  72  50  72  51  77 /  90   0   0   0  10   0
Colville       46  67  40  66  38  76 /  80   0  10  30  10   0
Sandpoint      46  59  42  61  41  71 /  90  30  10  10  10   0
Kellogg        43  58  44  63  45  70 / 100  50   0  10  20   0
Moses Lake     44  70  45  68  45  76 /  40   0   0   0  10   0
Wenatchee      49  70  53  67  52  75 /  40   0   0  30  10   0
Omak           47  71  50  68  46  77 /  80   0  10  60  10   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Flood Watch until 8 PM PDT this evening for Central Chelan
     County-Moses Lake Area-Northeast Mountains-Okanogan
     Highlands-Okanogan Valley-Upper Columbia Basin-Waterville
     Plateau-Wenatchee Area-Western Chelan County-Western
     Okanogan County.
ID...None.

&&

$$